diff --git a/libguile/environments.c b/libguile/environments.c
index a94f119cd..4534bab82 100644
--- a/libguile/environments.c
+++ b/libguile/environments.c
@@ -96,7 +96,7 @@ scm_error_environment_immutable_location (const char *func, SCM env, SCM symbol)
 SCM
 scm_make_environment (void *type)
 {
-  return scm_cell (scm_tc16_environment, (scm_t_bits) type);
+  SCM_RETURN_NEWSMOB (scm_tc16_environment, type);
 }
 
 
@@ -645,10 +645,12 @@ struct core_environments_base {
 static SCM
 core_environments_observe (SCM env, scm_environment_observer proc, SCM data, int weak_p)
 {
-  SCM observer = scm_double_cell (scm_tc16_observer,
-				  SCM_UNPACK (env),
-				  SCM_UNPACK (data),
-				  (scm_t_bits) proc);
+  SCM observer;
+
+  SCM_NEWSMOB3 (observer, scm_tc16_observer,
+		SCM_UNPACK (env),
+		SCM_UNPACK (data),
+		(scm_t_bits) proc);
 
   if (!weak_p)
     {